to give grand jury testimony for a sting operation. The blackmailer had threatened to write a book and screenplay detailing sexual affairs the talk show host had with female members of his staff and college student interns, who worked on The Late Show for college credit and to obtain high-profile work experience in the broadcasting industry. Letterman gave few details, except to say that he cooperated with police, wrote a "fake check" for $2 million, and that the blackmailer was apprehended. According to The New York Times, this segment was not transmitted via closed circuit inside the CBS headquarters, where employees usually are able to watch the Letterman show live. The revelation of the extortion plot was national news ahead of the show airing, leading to a 22% surge in ratings. 2010 August 31 Actor Michael Douglas, appearing on the Late Show to promote Wall Street: Money Never Sleeps, was interviewed by Letterman in what was the actor's first interview since Douglas went public with the fact that he has throat cancer. Douglas said he had already started treatment and doctors had given him 80% chance of a full recovery. 2011 August 22 A few days after a posting on the Shumukh al-Islam web forum that called for his assassination, Letterman opened his monologue with a joke referencing the threat: "Tonight, you people are ... more than an audience. You're more like a human shield." That evening, his Top Ten list, "Top 10 thoughts that went through my mind after hearing about the threat," included "Someone wants to silence me? Get in line," "This seems like Leno's handiwork" and "Oh my God! They canceled the George Lopez Show." In spite of the jokes, it had been made public a few days earlier that the threat had resulted in the tightening of security at the Ed Sullivan Theater. December 19 Letterman announced the death of long-time makeup artist Michele O'Callaghan, whom he had worked with since 1991. The episode featured a speech by Dave followed by a montage of O'Callaghan's onscreen appearances. 2012 February 1 Letterman celebrated his 30th anniversary on late night television with guest Howard Stern. The Top Ten List, Things Staffers Would Like to say to Dave on his 30th Anniversary in Late Night, was presented by staff members who had been with Letterman since his time at NBC. May 17 After 13 years, late-night talk show host